Field of the Invention
The field of the present invention relates to mechanical thrombectomy and catheter directed thrombolysis and for use in neurologic arteries where vessels are characterized by difficulty to deliver ablation devices thereinto due to the small size of the vessel and the tortuousity of the vessels. High efficacy of any thrombus or clot removing device is highly desirable when dealing with the removal of organized and difficult to remove materials which have been expelled from the left atrium or aorta. Furthermore, a guidewire-type catheter that is highly deliverable, such as by the use of a 0.014 inch guidewire such as provided by the present invention, can be utilized in the distal arteries of the coronary or peripheral arteries especially when such a catheter must be delivered through diseased vessel segments since it has a small crossing profile and is structurally suited for such a task.
Description of the Prior Art
Prior art devices such as thrombectomy catheters and closely related devices have been previously developed and designed to access and treat sites along the neurological anatomy. Such devices included catheters which were delivered within the vasculature in two parts. First, a microcatheter which is essentially a tube functioning as the effluent lumen of the thrombectomy catheter would be delivered to the treatment site over a guidewire. Then, a nitinol jet body with a guidewire tip on it was delivered inside the microcatheter to the treatment site. The jet body is the part of the thrombectomy catheter that delivers saline to the distal end of the catheter. The jet body has small jet orifices that are partly responsible for the high back pressures developed by the catheter. The jet orifices are positioned to direct high speed fluid jet streams within the catheter body. In previous neurological thrombectomy catheters, the jet body was designed to include a short skirt. When the jet body was activated by pumped saline, recovered pressures within the catheter assembly would expand the skirt such that the two parts became a unified single catheter assembly. The sequential exchange of devices meant that no guidewire was in place once the jet body was delivered. Hence, there was ample lumen for suitable exhaust flow and the catheter size could be kept smaller due to the absence of a guidewire. Generally, this two-part configuration for delivery to access and treat the site was difficult to accomplish. Some microcatheters would actually stretch while the jet body was advanced through the lumen, hence the jet body was never exposed to enable its activation. On occasions, the microcatheter would ovalize or otherwise distort in a tortuous anatomy, thus making it difficult to deliver the jet body through such a misshaped lumen. Furthermore, interventionalists are never comfortable giving up their wire position and removing the guidewire in exchange for a jet body was regarded as a bit awkward and non-intuitive. Previous versions of neurologic thrombectomy catheters were often underpowered for the tough thrombus that was found in embolic stroke patients (organized thrombus from the left atrium). With any given AngioJet® style catheter design, there is a tradeoff between the thrombectomy power of the catheter and the vessel safety of that catheter design. The essence of the problem is that neurological arteries are highly fragile since they have very thin and unsupported vessel walls and the clot material adhering thereto is tough and organized.
Currently produced 3Fr catheters are designed to be more easily deliverable to small distal vessels and they are envisioned to be an improvement over first generation products. The 3Fr catheters have a transitioned sized hypotube assembly which is intended to achieve a level of deliverability far superior to the currently available 4Fr catheters and, due to their smaller profile, will greatly enhance their deliverability. Nevertheless, the 3Fr catheter will not achieve the level of deliverability of a 0.014 inch infusion flow guidewire as discussed in the present invention. The crossing profile of 1.07Fr of the 0.014 inch infusion flow guidewire versus the 3Fr catheter is of substantial benefit. Furthermore, a catheter that rides over a guidewire will interact with the guidewire creating a drag which will diminish the ultimate deliverability of the catheter device, whereas a 0.014 inch infusion flow guidewire of the present invention does not have this problem.